Catnip, which is a member of the mint family, is an herb that was originally imported from the Mediterranean. Many cats go crazy for catnip because of the oils present in the stems, leaves and flowers. The chemical is very similar to the odor of a female cat in heat, which explains why male tomcats are most affected by catnip.

Dr. Cathy Lund of City Kitty Veterinary Care for Cats in Providence, R.I., explains, “The mint produces a weird, euphoric state, and about 50% of all cats are sensitive to its effects. Catnip is hallucinogenic and narcotic-like, and it acts as a dis-inhibitor, which is why cats get so wacky when they are under its influence.”

If your cat is not interested in catnip, don’t worry -- genetics actually determine if catnip will affect your cat. “If your cat is one of the 50% of cats who are not sensitive to the herb, then it won't have any appeal whatsoever,” Dr. Lund said. “And catnip never affects kittens until they are older than 3 months of age.”

If your cat is one of those who isn’t interested in catnip, there is another natural alternative that your cat may enjoy. “The only naturally-occurring herb that can induce a similar response in the genetically susceptible cats is valerian,” says Dr. Lund. “This herb is commonly found in homeopathic relaxation and anti-stress remedies.”